Human interleukin-4 (IL-4) is a natural protein which is believed to have a therapeutic potential against infection, cancer and autoimmune disease and was characterized by Yokota et al., Proc. Natl. Acad. Sci., USA, 83, 5894-5898 (1986). Mouse IL-4 is reported by Lee, et al., Proc. Natl. Acad. Sci. USA, 83, 2061-2065 (1986) and Noma, et al. Nature, 319, 640-646 (1986).
In the production of genetically engineered IL-4, separation of the expressed protein from the transformed host cells or their cultures supernatants can be a major problem, Dwyer, Biotechnology, 2, 957 (1984).
Clinical use of active IL-4 requires a high purity material that is not contaminated by cell constituents or cell debris of the IL-4 expressing cell. Accordingly, purification of active IL-4 in the cell culture medium of IL-4 expressing CHO-cell lines in high yields and high purity is needed.
This invention relates to purifying active soluble IL-4 resulting from its expression in certain CHO-cell lines.